Bullous pemphigoid is an autoimmune disease in which the autoantibodies themselves have been implicated in pathogenensis. The objective is to develop monoclonal antibodies to the putative antigens concerned with bullous pemphigoid. Long range goals are to develop a program in which the monoclonal antibodies can be utilized for elucidation of the disease and for its immunoregulation by suppressive anti-idiotypes. To achieve our primary goal, hybridoma fusions will be performed with spleen cells from rats and mice immunized with pemphigoid antigens, or with lymphocytes from selected pemphigoid patients. Fusion partners will consist of established malignant cell lines of either murine or human origin. The resulting hybridomas that secrete antibody to epidermal antigens will be identified by indirect immunofluorescence. These cell lines will be cloned to produce monoclonal antibodies. The monoclonal antibodies will be characterized for their tissue specificity by indirect immunofluorescence and for their reactivity to epidermal epitopes by immunoblotting techniques. The immunochemical properties of the monoclonal antibodies will also be determined. These properties will include isoelectric point and apparent molecular weight (by 2-dimensional polyacrylamide gel electrophoresis), class, and subclass. The monoclonal antibodies will also be useful for purification of antigen and for the exploration of the biological mechanisms of pathogenesis. The latter will involve an in vitro assay for epidermal cell attachment to a solid substrate. Monoclonal antibodies, individually or in combination, will be incubated with epidermal basal cell suspensions. Inhibition of cell attachment to the substrate following incubation with antibody, may indicate and involvement of the bullous pemphigoid antigen(s) with the epidermal basal cell-substrate interaction.